The 3rd Generation Partnership Project, also referred to as “3GPP,” is a collaboration agreement that aims to define globally applicable Technical Specifications and Technical Reports for 3rd Generation Systems. 3GPP Long Term Evolution (LTE) is the name given to a project to improve the Universal Mobile Telecommunications System (UMTS) mobile phone or device standard to cope with future requirements. The 3GPP may define specifications for the next generation mobile networks, systems, and devices. In one aspect, UMTS has been modified to provide support and specification for the Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN). In 3GPP LTE a mobile terminal or device is called a “user equipment” (UE) and a relaying station is called a “relay node.” A base station may be referred to as an evolved NodeB (eNodeB).
One of the current goals of the 3GPP LTE and WiMAX standardization work is to improve the cell edge throughput and coverage for edge users. Among the different proposals being considered, one of the proposals is to use relay nodes to relay the information from the base station to the mobile terminal and vice-versa. The use of relay nodes has been adopted for use in the Institute of Electrical and Electronics Engineers (IEEE) 802.16m and the Worldwide Interoperability for Microwave Access (WiMax) technologies.
Resource scheduling means the eNodeB allocates the modulation schemes, coding rates, time slot and subcarrier frequencies to optimize the downlink and uplink transmissions for each UE. Because of varying quality of service (QoS) and security requirements, the retransmission of signals may be prevented because these signals may cause interference, consume unnecessary power, and lower the capacity of the network.
Wireless channels suffer from path loss, shadowing, and multipath effects that can degrade signal quality. The use of relay nodes may improve the cell-edge performance of a UE because the distance from the relay to the UE is much less than the distance from the relay to the eNodeB.
Therefore, improvements in wireless networks can be obtained by improving cell-edge performance and reducing/removing inter-relay interference without causing degradation in the system performance.